Hitherto, a rolling guide device of this type includes a track member and a moving member. The track member has a rolling surface for rolling elements, which extends along a longitudinal direction of the track member. The moving member is assembled to the track member through intermediation of a large number of rolling elements which roll on the rolling surface, and is reciprocable along the track member. The moving member has a load rolling surface on which the rolling elements roll while bearing a load. The load rolling surface is opposed to the rolling surface of the track member to define a load path for the rolling elements. Further, the moving member has no-load paths for allowing the rolling elements to circulate from one end to another end of the load path. The load path and the no-load paths are continuous with one another to define an endless circulation path for the rolling elements. With such a configuration, the moving member is movable along the track member without being limited in stroke thereof.
A product lifetime of the rolling guide device mainly depends on fatigue in the rolling surface of the track member ox the load rolling surface of the moving member. However, when the rolling surface and the load rolling surface as well as the rolling elements such as balls or rollers which roll thereon are not appropriately lubricated with lubricant, flaking of the rolling surface or the load rolling surface may occur early, with the result that the product lifetime of the rolling guide device is shortened. When lubrication defect occurs, rolling resistance of the rolling elements increases. As a result, there is a fear in that, for example, acceleration of the table which is movably supported by the rolling guide device is degraded, that is, the rolling guide device cannot exert its original performance.
Meanwhile, the rolling guide device is applicable to various uses, and a lubrication state of the rolling surface or other part is inevitably affected by, for example, a use environment and an applied load depending on the use (hereinafter referred to as “use condition”). Thus, in order to allow the rolling guide device to exert its original performance and fulfill its product lifetime, it is desired that an operation condition of the rolling guide device be continuously detected by various sensors and that supply of the lubricant be controlled based on results of detection. Further, it is also desired that an operation of an industrial machine having the rolling guide device incorporated therein be controlled as needed.
Patent Literature 1, there is disclosed an example in which a sensor configured to detect presence of lubricant on the track member is mounted to the moving member. However, the sensor is mounted on an outer side of the moving member. Thus, even though the fact of whether or not the lubricant adheres to the track member can be checked, a lubrication state and a circulation state of the rolling elements in the endless circulation path of the moving member cannot be directly recognized.